1. Technical Field
The present invention relates to a display device with a touch detection function and a display system.
2. Description of the Related Art
Display panels with a touch detection function have recently been attracting attention. Such display panels are obtained by mounting a contact detecting device called a touch panel on a display device, such as a liquid-crystal display device, or integrating the touch panel with the display device. The display panels display various button images and other images on the display device instead of having typical mechanical buttons to receive information. Because the display panels with a touch panel require no input device, such as a keyboard, a mouse, or a keypad, they are increasingly used with computers, portable electronic apparatuses, such as mobile phones, and other equipment.
Examples of touch panel technologies include optical, resistive, and capacitive technologies. Capacitive touch panels, for example, are used as a touch panel integrated with a display panel to constitute a display panel with a touch detection function of a display device. In such a display device, common electrodes for display originally included in the display device are also used as drive electrodes for touch detection.
Display devices with a touch detection function designed for electronic apparatuses, such as mobile phones and tablets, preferably have a normal operation mode and a sleep mode. In the normal operation mode, the display devices with a touch detection function perform both image display and touch detection. In the sleep mode, the display devices with a touch detection function stop displaying an image and cause each unit to stop operating when no operation is performed for a certain period of time, thereby reducing power consumption.
Japanese Patent Application Laid-open Publication No. 2014-241049 (JP-A-2014-241049), for example, describes a display device with a touch detection function. In a sleep mode, the display device determines whether a touch operation is performed using a self-capacitive technology. If the display device detects a touch operation, the display device detects a touch coordinate position and a gesture (movement of an external proximity object, such as a finger) using a mutual-capacitive technology. If the display device detects a predetermined gesture, the display device shifts to a normal operation mode.
The display device with a touch detection function described in JP-A-2014-241049 detects a touch coordinate position and/or a gesture using the mutual-capacitive technology in the sleep mode. In typical display devices with a touch detection function obtained by integrating a display panel with a touch panel, not only common electrodes but also a component that drives the common electrodes as drive electrodes for touch detection is shared for display use and touch detection use. The component that drives the common electrodes as drive electrodes for touch detection is frequently included in a device for display. Therefore, a case where a display device with a touch detection function obtained by integrating a display panel with a touch panel performs a gesture detection function using the mutual-capacitive technology in the sleep mode may possibly require high power consumption, compared with a case where a display device including a display panel with a touch detection function obtained by providing a touch panel on a display surface of a display device of a device for display control performs a gesture detection function in the sleep mode.
For the foregoing reasons, there is a need for a touch detecting device, a display device with a touch detection function, and a display system that provide low power consumption when performing a gesture detection function in a sleep mode as a configuration including a display panel with a touch detection function obtained by integrating a display panel with a touch panel.